For example, U.S. Pat. No. 5,520,547 (JP-A-7-91343), and U.S. Pat. No. 6,478,613 (JP-T-2002-544425) disclose fuel pumps each having a case member accommodating a pump portion and a motor portion. The pump portion is driven by an armature of the motor portion.
As disclosed in U.S. Pat. No. 5,520,547, a fuel pump includes a discharge-side cover and case members. The cover and the case members respectively have an outlet and an inlet, and define fuel passages therein. The discharge-side cover includes a bearing holder being insulative and mounted with positive and negative electrode terminals.
The motor portion is supplied with electricity from an external power source via the positive and negative electrode terminals.
Here, a gasoline-alternate fuel, such as high density alcohol petroleum fuel mixture, bio-ethanol, ethanol 100% fuel, and the like, is in great demand. The gasoline-alternate fuel contains a component of high electric conductivity therein. When conventional pumps for gasoline fuel are to be applied to a fuel pump for a gasoline-alternate fuel, as it is, a problem described below is caused.
Specifically, with the fuel pump described in U.S. Pat. No. 5,520,547, the load bearing portions are provided on both the terminals, and are exposed to the fuel passage. In this structure, the terminals are exposed entirely to the gasoline-alternate fuel containing a component of high conductivity, and consequently, the terminals cause electrochemical corrosion due to exposure to gasoline-alternate fuel.
Such an electric corrosion is apt to occur as the distance between both the terminals becomes short. However, when both the terminals are arranged simply further distant from each other, the fuel pump becomes large in size.